What must be true of a person with cystic fibrosis?
a. at least one parent was a carrier for cystic fibrosis.
b. the mother was a carrier for cystic fibrosis.
c. one of the parents had the condition cystic fibrosis.
d. both parents had at least one allele for cystic fibrosis.

Astudent wants to test the hypothesis that fertilizer improves the growth rate of grass seeds. to test this hypothesis, the student put the same amount of grass seed in 3 containers with the same type of soil. the student measured the growth at the end of the week. all plants received equal amounts of water and sunlight. if you were asked to graph this data, what would you place on the x-axis? a. fertilizer b. water c. plant growth d. week one